I'm in the midst of a restoration project and have three out of four fittings where the crossbars join the hulls leaking a little air on a leak test. Can I just seal around the fittings without removing them, or do I have to take out the 5 or 6 factory installed screws, remove the fittings, and reseat them? Whichever, is silicone the best bet, or is there something better?

Thanks!

I would take the time and remove the crossbars, sand the saddles where the beams set, use a good silicone sealant and put a bead in the saddle from one side of the hull to the other in a continous circle, and also another circle around the holes where the bolts go through if needed such as a P-19. This process will act like a gasket, and the beams will sit proper with a good seal.

3M 5200. seals and stays, forever

When I restored my P19, the hull seat under the cross bars was in pretty bad shape. I think with time the original silicone degraded and sand/debris found its way between the cross bar and the hull. Sealing the outside wont help because there is some flex or movement between the bar and hull. I had to sand the seat , fair it with epoxy and seal like explained in the other posts, used silione instead of 5200.

I would not use 5200. Dealer said to use something else. 5200 is permanent. BE REAL careful!!!

Doug

Thanks, everyone. I'm planning to seal them tomorrow with 100% pure silicone.

Hi,
Could you post some pictures?

//P

I've heard that a product called Anti-Bond, available at West Marine, is very effective at removing and de-bonding 5200.

It is if it's a thin bead of 5200. If it's a large contact patch that's filled with 5200, forget it. I know someone who inherited a boat on which the beams were seated with 5200. After trying every chemical known to man, the beam eventually claimed part of the deck before it was removed from the boat.

That's the warning I've encountered regarding 5200--it's great when you really want something permanently bonded, but not for sealing a fitting that will need to be removed in the future. Our local sailing shop guru says that 5200 should be considered a cement rather than a sealer. Anyway, that's why I'm going to do the silicone instead. Unfortunately, very damp conditions today will keep my from doing anything until tomorrow. <img src="http://www.catsailor.com/forums/images/graemlins/frown.gif" alt="" />

A polyurethane adhesive/sealant that is very similar to 3M Marine Adhesive/Sealant 5200, but that is about half the strength, which allows for disassembly of parts. 4200 delivers flexible bonds with good adhesion to wood, fiberglass, gelcoat, certain plastics, and metals. It is paintable and sandable, and forms watertight, weather-resistant seals on joints and boat hardware above or below the waterline.

Agree... 4200. I have used it on RV windows and body seams, sealing screws and bolts in boats, etc. It remains flexible and holds until you want to remove it.

Silicone should not really be used on anything that flexes, moves, vibrates. Vibration alone will cause silicone to release. Save it for your bath tub.

Guys:

I couldn't remember the number, but 4200 is what the dealer wants to use to rebond my crossbars on my 17 to stop water coming in as a winter project.

Doug

OK, did a little MORE research and am now glad it was too wet to apply silicone today! Instead, I'll be using the 4200 tomorrow. Will let you know if it still leaks afterwards, though it will take a week or two to get to the point of leak testing again. Ah, what else to do over the holidays anyway? <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />